// Copyright 2012 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#if V8_TARGET_ARCH_IA32

#include "src/deoptimizer.h"
#include "src/frame-constants.h"
#include "src/macro-assembler.h"
#include "src/register-configuration.h"
#include "src/safepoint-table.h"

#include "src/objects-inl.h" // weolar

namespace v8 {
namespace internal {

#define __ masm->

    void Deoptimizer::GenerateDeoptimizationEntries(MacroAssembler* masm,
        Isolate* isolate,
        DeoptimizeKind deopt_kind)
    {
        NoRootArrayScope no_root_array(masm);

        // Save all general purpose registers before messing with them.
        const int kNumberOfRegisters = Register::kNumRegisters;

        const int kDoubleRegsSize = kDoubleSize * XMMRegister::kNumRegisters;
        __ sub(esp, Immediate(kDoubleRegsSize));
        const RegisterConfiguration* config = RegisterConfiguration::Default();
        for (int i = 0; i < config->num_allocatable_double_registers(); ++i) {
            int code = config->GetAllocatableDoubleCode(i);
            XMMRegister xmm_reg = XMMRegister::from_code(code);
            int offset = code * kDoubleSize;
            __ movsd(Operand(esp, offset), xmm_reg);
        }

        STATIC_ASSERT(kFloatSize == kSystemPointerSize);
        const int kFloatRegsSize = kFloatSize * XMMRegister::kNumRegisters;
        __ sub(esp, Immediate(kFloatRegsSize));
        for (int i = 0; i < config->num_allocatable_float_registers(); ++i) {
            int code = config->GetAllocatableFloatCode(i);
            XMMRegister xmm_reg = XMMRegister::from_code(code);
            int offset = code * kFloatSize;
            __ movss(Operand(esp, offset), xmm_reg);
        }

        __ pushad();

        ExternalReference c_entry_fp_address = ExternalReference::Create(IsolateAddressId::kCEntryFPAddress, isolate);
        __ mov(masm->ExternalReferenceAsOperand(c_entry_fp_address, esi), ebp);

        const int kSavedRegistersAreaSize = kNumberOfRegisters * kSystemPointerSize + kDoubleRegsSize + kFloatRegsSize;

        // The bailout id is passed in ebx by the caller.

        // Get the address of the location in the code object
        // and compute the fp-to-sp delta in register edx.
        __ mov(ecx, Operand(esp, kSavedRegistersAreaSize));
        __ lea(edx, Operand(esp, kSavedRegistersAreaSize + 1 * kSystemPointerSize));

        __ sub(edx, ebp);
        __ neg(edx);

        // Allocate a new deoptimizer object.
        __ PrepareCallCFunction(6, eax);
        __ mov(eax, Immediate(0));
        Label context_check;
        __ mov(edi, Operand(ebp, CommonFrameConstants::kContextOrFrameTypeOffset));
        __ JumpIfSmi(edi, &context_check);
        __ mov(eax, Operand(ebp, JavaScriptFrameConstants::kFunctionOffset));
        __ bind(&context_check);
        __ mov(Operand(esp, 0 * kSystemPointerSize), eax); // Function.
        __ mov(Operand(esp, 1 * kSystemPointerSize),
            Immediate(static_cast<int>(deopt_kind)));
        __ mov(Operand(esp, 2 * kSystemPointerSize), ebx); // Bailout id.
        __ mov(Operand(esp, 3 * kSystemPointerSize), ecx); // Code address or 0.
        __ mov(Operand(esp, 4 * kSystemPointerSize), edx); // Fp-to-sp delta.
        __ mov(Operand(esp, 5 * kSystemPointerSize),
            Immediate(ExternalReference::isolate_address(isolate)));
        {
            AllowExternalCallThatCantCauseGC scope(masm);
            __ CallCFunction(ExternalReference::new_deoptimizer_function(), 6);
        }

        // Preserve deoptimizer object in register eax and get the input
        // frame descriptor pointer.
        __ mov(esi, Operand(eax, Deoptimizer::input_offset()));

        // Fill in the input registers.
        for (int i = kNumberOfRegisters - 1; i >= 0; i--) {
            int offset = (i * kSystemPointerSize) + FrameDescription::registers_offset();
            __ pop(Operand(esi, offset));
        }

        int float_regs_offset = FrameDescription::float_registers_offset();
        // Fill in the float input registers.
        for (int i = 0; i < XMMRegister::kNumRegisters; i++) {
            int dst_offset = i * kFloatSize + float_regs_offset;
            __ pop(Operand(esi, dst_offset));
        }

        int double_regs_offset = FrameDescription::double_registers_offset();
        // Fill in the double input registers.
        for (int i = 0; i < config->num_allocatable_double_registers(); ++i) {
            int code = config->GetAllocatableDoubleCode(i);
            int dst_offset = code * kDoubleSize + double_regs_offset;
            int src_offset = code * kDoubleSize;
            __ movsd(xmm0, Operand(esp, src_offset));
            __ movsd(Operand(esi, dst_offset), xmm0);
        }

        // Clear FPU all exceptions.
        // TODO(ulan): Find out why the TOP register is not zero here in some cases,
        // and check that the generated code never deoptimizes with unbalanced stack.
        __ fnclex();

        // Remove the return address and the double registers.
        __ add(esp, Immediate(kDoubleRegsSize + 1 * kSystemPointerSize));

        // Compute a pointer to the unwinding limit in register ecx; that is
        // the first stack slot not part of the input frame.
        __ mov(ecx, Operand(esi, FrameDescription::frame_size_offset()));
        __ add(ecx, esp);

        // Unwind the stack down to - but not including - the unwinding
        // limit and copy the contents of the activation frame to the input
        // frame description.
        __ lea(edx, Operand(esi, FrameDescription::frame_content_offset()));
        Label pop_loop_header;
        __ jmp(&pop_loop_header);
        Label pop_loop;
        __ bind(&pop_loop);
        __ pop(Operand(edx, 0));
        __ add(edx, Immediate(sizeof(uint32_t)));
        __ bind(&pop_loop_header);
        __ cmp(ecx, esp);
        __ j(not_equal, &pop_loop);

        // Compute the output frame in the deoptimizer.
        __ push(eax);
        __ PrepareCallCFunction(1, esi);
        __ mov(Operand(esp, 0 * kSystemPointerSize), eax);
        {
            AllowExternalCallThatCantCauseGC scope(masm);
            __ CallCFunction(ExternalReference::compute_output_frames_function(), 1);
        }
        __ pop(eax);

        __ mov(esp, Operand(eax, Deoptimizer::caller_frame_top_offset()));

        // Replace the current (input) frame with the output frames.
        Label outer_push_loop, inner_push_loop,
            outer_loop_header, inner_loop_header;
        // Outer loop state: eax = current FrameDescription**, edx = one
        // past the last FrameDescription**.
        __ mov(edx, Operand(eax, Deoptimizer::output_count_offset()));
        __ mov(eax, Operand(eax, Deoptimizer::output_offset()));
        __ lea(edx, Operand(eax, edx, times_system_pointer_size, 0));
        __ jmp(&outer_loop_header);
        __ bind(&outer_push_loop);
        // Inner loop state: esi = current FrameDescription*, ecx = loop
        // index.
        __ mov(esi, Operand(eax, 0));
        __ mov(ecx, Operand(esi, FrameDescription::frame_size_offset()));
        __ jmp(&inner_loop_header);
        __ bind(&inner_push_loop);
        __ sub(ecx, Immediate(sizeof(uint32_t)));
        __ push(Operand(esi, ecx, times_1, FrameDescription::frame_content_offset()));
        __ bind(&inner_loop_header);
        __ test(ecx, ecx);
        __ j(not_zero, &inner_push_loop);
        __ add(eax, Immediate(kSystemPointerSize));
        __ bind(&outer_loop_header);
        __ cmp(eax, edx);
        __ j(below, &outer_push_loop);

        // In case of a failed STUB, we have to restore the XMM registers.
        for (int i = 0; i < config->num_allocatable_double_registers(); ++i) {
            int code = config->GetAllocatableDoubleCode(i);
            XMMRegister xmm_reg = XMMRegister::from_code(code);
            int src_offset = code * kDoubleSize + double_regs_offset;
            __ movsd(xmm_reg, Operand(esi, src_offset));
        }

        // Push pc and continuation from the last output frame.
        __ push(Operand(esi, FrameDescription::pc_offset()));
        __ push(Operand(esi, FrameDescription::continuation_offset()));

        // Push the registers from the last output frame.
        for (int i = 0; i < kNumberOfRegisters; i++) {
            int offset = (i * kSystemPointerSize) + FrameDescription::registers_offset();
            __ push(Operand(esi, offset));
        }

        // Restore the registers from the stack.
        __ popad();

        __ InitializeRootRegister();

        // Return to the continuation point.
        __ ret(0);
    }

    bool Deoptimizer::PadTopOfStackRegister() { return false; }

    void FrameDescription::SetCallerPc(unsigned offset, intptr_t value)
    {
        SetFrameSlot(offset, value);
    }

    void FrameDescription::SetCallerFp(unsigned offset, intptr_t value)
    {
        SetFrameSlot(offset, value);
    }

    void FrameDescription::SetCallerConstantPool(unsigned offset, intptr_t value)
    {
        // No embedded constant pool support.
        UNREACHABLE();
    }

#undef __

} // namespace internal
} // namespace v8

#endif // V8_TARGET_ARCH_IA32
